1. Field of the Invention
The present invention generally relates to industrial cleaning processes and devices. More particularly, it relates to a method and apparatus for cleaning petroleum residuum from tanks such as railroad tank cars.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
In the past, rail tank cars have been cleaned using large and complex equipment requiring multiple operators and an assortment of chemicals, typically water based. In addition to these methods, it is common to place personnel inside the tank cars to perform a final hydroblasting/cleaning step prior to inspection. These methods require several dispensing tanks, pumps, valves, filters, exchangers, air scrubbers and distribution equipment. Confined space entry of personnel also requires the use of a self-contained breathing apparatus (SCBA) or ‘fresh air’ during the entire entry period since the environment inside the tank can be immediately dangerous to life and health (IDLH).
Most of the cleaning systems of the prior art are immobile, expensive and the process is time consuming. They also generate large amounts of water and hydrocarbon effluent requiring special treatment and disposal methods. In addition, legacy processes require water rinsing which contributes to the effluent volume and creates flash rusting inside the tank.